The present invention relates to wireless communication systems and, more particularly, relates to encoding data in the horizontal overscan portion of a video signal.
A variety of consumer products available today rely upon the use of wireless communication. Examples include cordless phones, garage door openers, remotely controlled appliances, and remotely controlled toys. A common motivation that drives manufacturers of these and similar products is minimizing the cost associated with providing the wireless communication capability. Thus, techniques for minimizing the cost of radio equipment for transmitting and receiving radio frequency signals while maintaining reliable communication are continuously explored.
Interactive toys, games, and learning products for the home could be particularly useful applications of wireless communication technology. Wireless systems eliminate the use of wire-line communication links and, therefore, are preferable for many household applications. For example, wireless toys, games, and learning products eliminate wires that small children might tangle or pull free, or that dogs might chew. Wireless products also avoid the need for universal plugs or adapters and allow a large number of wireless devices to be controlled by a single controller without requiring a large terminal port for plugging-in the controlled devices. Wireless communication links are therefore safer, more robust, more versatile, and in many cases less expensive than wire-line communication links.
There are a number of often competing objectives in designing wireless products, such as toys, games, and learning products, for use in a home environment. First, the entire system should be priced within an acceptable range for a children""s entertainment product. Furthermore, because each child may desire new controlled devices over time, the cost of each controlled device should be as low as possible. This means that the controlled devices should include inexpensive wireless communication equipment, such as conventional amplitude modulation (AM) radio equipment and digital data handling equipment.
Second, it is advantageous for several wireless devices to be controlled simultaneously by a single controller. In the context of a wireless toy environment, this allows several children to interact with their own toys at the same time. For example, one child may interact with a xe2x80x9cFREDxe2x80x9d toy, while another interacts with a xe2x80x9cWILMAxe2x80x9d toy, while yet another interacts with a xe2x80x9cDINOxe2x80x9d toy, etc. In addition, it is advantageous for a variety of different toys to be available so that children have a selection of toys to choose from and collect. Moreover, in a progressive learning system, it is advantageous to have a series of toys associated with different skills so that a child can progress through the skills learned by interacting with the different toys.
Third, it is advantageous for the controller and the controlled devices to be operable for engaging in bidirectional communications. This is particularly useful in an interactive learning environment in which a child interacts with a controlled device. For example, the controller may direct a controlled doll to say, xe2x80x9cPlease squeeze my left hand.xe2x80x9d The controlled doll may then transmit the child""s response back to the controller, which responds accordingly. For example, if the child squeezes the doll""s right hand, the controller directs the doll to say, xe2x80x9cNo that""s my right hand, please squeeze my left hand.xe2x80x9d
A fourth consideration is forward compatibility. This means that the original controller can be used to operate future versions of controlled devices. For example, an interactive toy product may initially be introduced with only one or two controlled devices (e.g., xe2x80x9cFREDxe2x80x9d and xe2x80x9cWILMAxe2x80x9d). But over the next several years, dozens of new controlled products may be released to upgrade the system (e.g., xe2x80x9cDINO,xe2x80x9d xe2x80x9cBAM-BAM,xe2x80x9d etc.). Forward compatibility allows the new controlled devices to be operated by the original controller.
In addition, control data must be provided to the controller, which in turn transmits the control data to the controlled devices through a local wireless communication link. Although the control data may be generated locally, for example by a computer located in close proximity to the controller, it is also desirable to transmit the control data from a remote location using a broadcast-level communication link, such as an air-wave or cable television signal. In particular, it would be advantageous to broadcast the control data along with a standard video signal for driving a display device, such as a television or monitor. In this manner, the controlled devices may be caused to operate in synchronism with the programming information defined by the video signal. For example, a controlled device may operate as a character in a video program displayed on the television or monitor.
In order to effectively broadcast the control data in connection with a video signal, several often competing objectives should be attained. First, as noted above, the control data should be temporarily synchronized with the video signal so that the actions of the controlled devices operate in synchronism with the programming information displayed on the television or monitor. Second, the control data should be easily concatenated with a standard video signal for transmission in a variety of broadcast media using standard equipment. Third, the control data should not interfere with the video signal or visibly disrupt the display of the video signal. Fourth, sufficient bandwidth should be provided in the upstream communication link (e.g., a broadcast-level communication link) to fully satisfy the bandwidth requirements of the downstream communication link (e.g., local wireless communication link). In addition, it would be advantageous for additional bandwidth to be available in the upstream communication link for transmitting additional information for other data sinks to provide advertising, subscription, or emergency warning services, such as e-mail, foreign language subtitling, telephone pages, weather warnings, configuration data for a set-top box, and so forth. It would also be advantageous for the bandwidth of the upstream communication link to be adjustable to meet the cost and performance needs of a wide variety of consumers.
As with the downstream wireless communication link, the protocol for the upstream communication link should be addressable so that several wireless controlled devices, as well as other data sinks, may be controlled simultaneously. The protocol should also be error tolerant and accommodate forward compatibility for future wireless controlled devices and other services that may be provided through the broadcast media. All of these attributes should be implemented at a-cost that is feasible to deploy in connection with a system that is primarily intended to be a children""s entertainment product.
There is, therefore, a need for a method and system for encoding control data for wireless controlled devices in connection with a video signal so that the actions of the controlled devices operate in synchronism with the programming information defined by the video signal. There is a further need for a method and system for encoding additional data in connection with the video signal for providing services, such as e-mail, intercom capability, foreign language subtitling, telephone pages, weather warnings, configuration data for a set-top box, and so forth. There is a further need for a protocol for encoding data in connection with a video signal that is be addressable, forwardly compatible, error tolerant, and feasible to deploy in connection with a system that is primarily intended to be a children""s entertainment product.
The present invention meets the needs described above by providing a method and system for encoding control data in the horizontal overscan portion of a video signal. Because the control data is concatenated with the video signal on a line-by-line basis, the control data is temporarily synchronized with the underlying video signal. This permits the controlled devices, such as wireless mechanical characters, to behave as characters in a scene defined by the programming information of the video signal. A protocol is defined for the encoded data that is addressable, forwardly compatible, error tolerant, and feasible to deploy in connection with a system that is primarily intended to be a children""s entertainment product. The bandwidth of the communication link defined by the encoded data is adjustable to meet the cost and performance needs of a wide variety of consumers. Sufficient bandwidth is available to control several devices and to provide additional advertising, subscription, or emergency warning services, such as e-mail, foreign language subtitling, intercom capability, telephone pages, weather warnings, configuration data for a set-top box, and so forth.
Generally described, the invention provides a method for encoding control data in a video signal that includes a series of frames that each include a number of lines. The encoded data is concatenated with the lines of the video signal to create an encoded video signal, which is configured to define content data in association with each frame. The content data is configured to define a first address associated with a first device, device-specific control data for the first device, a second address associated with a second device, and device-specific control data for the second device. In response to the first address, the device-specific control data for the first device is routed to the first device and the actions of the first device are controlled accordingly. Similarly, in response to the second address, the device-specific control data for the second device is routed to the second device and the actions the second device are controlled accordingly.
The video signal typically defines programming information including a scene displayed on a display device. The device-specific control data for the first device typically includes voice and motor control data that causes the first device to behave as a character in the scene displayed on the display device. The device-specific control data for the second device may be voice or motor control data that causes the second device to behave as a second character in the scene displayed on the display device, electronic mail for a transmission to a computer system, intercom information for transmission to an intercom system, telephone paging information for transmission to a paging system, or language translation information, advertising information, subscription information, or emergency warning information displayed on the display device. Many other specific applications will be apparent to those skilled in the art.
The addressing scheme for the device-specific control data implements a versatile and extensible packet-based data transmission format. For example, the first address may be a first start-packet short address word for a first controlled device, and the second address may be a second start-packet short address word for a second controlled device. In this case, the second start-packet short address word may be interpreted as an end-packet short address word for the first controlled device.
In addition, the first address may define a start-packet begin-long-address word. In this case, the content data also defines a first occurrence of a long address associated with the first device, and a start-packet end-long-address word associated with the first device, device-specific control data for the first device.
According to an aspect of the invention, the encoded data may include signal detection words and content words. Each signal detection word and each content word may include data bits and error correction bits that are used to correct errors in the data bits. Specifically, the error correction bits may define a correction sequence that allows a single-bit error in the data bits to be detected and corrected. Each signal detection word may include four data bits and three error correction bits, and each content word may include nine data bits and seven error correction bits.
According to another aspect of the invention, a signal detection word may be encoded into each frame of the video signal such that a consecutive series of the signal detection words defines a dynamic validation sequence. For this sequence, each signal detection word varies in at least two bits from the immediately preceding signal detection word. For example, the dynamic validation sequence transmitted in consecutive fields of a two-field interlaced frame of the video signal may include the binary representation of 8, 1, 10, 3, 12, 5, 14, 7.
According to yet another aspect of the invention, the encoded data is defined by line signals located in the horizontal overscan portion of a video signal. Specifically, each line signal may be a pre-visible pulse located between the color burst portion and the visible raster portion of a horizontal scan line of the video signal. Each pulse may define a single bit of the encoded data, in which case the encoded data of each field of a two-field interlaced frame of the video signal may define one 7-bit signal detection word and 13 16-bit content words. To increase the bandwidth of the encoded data transmission, each line signal may include both a pre-visible pulse and a post-visible pulse located after the visible raster portion and before the horizontal blanking interval. To further increase the bandwidth of the encoded data transmission, each pulse may be modulated to define several bits.
The invention also provides an encoded video signal, which is created according to the method described above, and a system for creating and using the encoded video signal. The system includes a video data encoder that is functionally connected to a video source that provides a video signal, such as an NTSC television signal. The video data encoder receives the video signal, which includes a series of frames that each include a number of lines. The video data encoder concatenates encoded data with the lines of the video signal to create the encoded video signal.
The video data encoder is functionally connected to data decoder that receives the encoded video signal from the video data encoder. The data decoder detects the presence of the signal detection data, extracts the content data from the encoded video signal, and assembles the content data into a serial data communication signal. The data decoder is functionally connected to a data error processor that receives the serial data communication signal from the data decoder. The data error processor parses the serial data communication signal into data bits and error corrections bits, analyzes the error correction bits to detect errors in the data bits, corrects detected errors in the data bits, and assembles the corrected data bits into an error corrected data stream.
The data error processor is functionally connected to a protocol handler that receives the error corrected data stream from the data error processor. The protocol handler detects a first start-packet short address word associated with a first device and, in response, begins the routing of subsequently received device-specific control data to the first device. The protocol handler also detects a second start-packet short address word associated with the second device and, in response, begins the routing of subsequently received device-specific control data to the second device. The protocol handler also interprets the second start-packet short address word as a first end-packet short address word associated with the first device and, in response, discontinues the routing of subsequently received device-specific control data to the first device.
The protocol handler also detects a start-packet start-long-address word, detects a long address associated with a third device, detects a start-packet end-long-address word, and begins the routing of subsequently received device-specific control data to the third device. To end the transmission to the third device, the protocol handler detects a further address word and, in response, discontinues the routing of subsequently received device-specific control data to the third device.
That the invention improves over the drawbacks of the prior art and accomplishes these advantages will become apparent from the following detailed description of the exemplary embodiments and the appended drawings and claims.